Project Summary The goals of this administrative supplement project are to undertake systematic evaluation of a subset of the protein capture reagents (antibodies) that have been generated by the NIH Common Fund Protein Capture Reagents Program (PCRP). Our goals are to: (1) validate each antibody by Western blot analysis; (2) evaluate each antibody by protein binding microarray (PBM) or other in vitro DNA binding assay; (3) perform computational motif enrichment analysis of antibodies assayed by ChIP-Seq or ChIP-exo in other PCRP labs; (4) generate a report file for each antibody from each validation assay. These biochemical validation assays will evaluate the ability of these antibodies to recognize their target transcription factors in solution and also when bound to DNA in vitro, while and the motif enrichment analysis will seek to provide support for the antibody detecting TF bound in vivo directly to its genomic target sites or potentially indirectly through co-regulatory factors. These validation assays will extend the utility of the PCRP capture reagents as a resource to the community by demonstrating the utility of the capture reagents to recognize transcription factors bound to DNA.